In a technical field related to such antennas, as is generally known, various types of antennas are mounted to a vehicle. For example, a GPS (Global Positioning System) antenna, an ETC (Electronic Toll Collection System) antenna, a VICS (Vehicle Information and Communication System) antenna, a telephone antenna and the like are mounted to the vehicle.
Specifically, the GPS (Global Positioning System) employs a satellite positioning system by use of a satellite. The GPS receives electric waves such as GPS signals from four satellites out of twenty-four earth-orbiting satellites. By measuring a positional relation and a time error between a movable body on the earth and the satellite, on the basis of the principle of the trigonometrical survey, the GPS computes a position and an altitude of the movable body on a map or the like with high accuracy.
The GPS is used for a car navigation system or the like for detecting a position of a running vehicle, and such system has been widely used. A car navigation device includes a GPS antenna, a processing device, a displaying device and the like. Specifically, the GPS antenna receives the GPS signal from the satellite, the processing device detects a current position of the running vehicle by processing the received GPS signal, and the display device displays the detected current position of the running vehicle on a map or the like.
The ETC (Electronic Toll Collection) is a system which was developed for easing traffic jams at tollgates, at which a passenger pays a toll for an expressway. Specifically, the ETC is a system by which the toll is automatically paid by the passenger at the tollgate by means of a wireless communication system. More specifically, the vehicle equipped with a communicating device having an ETC antenna two-way communicates with an antenna provided at the tollgate in order to receive information from the vehicle, and the toll can be paid automatically at the tollgate without requiring the vehicle to stop.
A known compound antenna apparatus equipped with the GPS antenna, the VICS (Vehicle Information and Communication System) antenna and the ETC antenna is disclosed in JP2004-56773A.
In the known compound antenna apparatus disclosed in JP2004-56773A, the GPS antenna and the VICS antenna are mounted to a circuit board, and the ETC antenna is independently mounted to the vehicle as a sub assembly. That is, when those antennas are mounted to the vehicle, a direction of the ETC antenna can be controlled separately from that of the GPS antenna and the VICS antenna because directional characteristics of the ETC antenna differs from that of the GPS antenna and the VICS antenna.
In the known compound antenna apparatus disclosed in JP2004-56773A, the cables connected to the antennas are pulled out from the apparatus, however, tensile strength of the cables in the direction in which the cables are pulled out is not considered. Thus, resulting in low tensile strength in the direction where the cables are pulled.
In the compound antenna apparatus, the cables may be fixed to brackets by lock bands in order to maintain the tensile strength of the cables. However, a large space is required to fix the cables by means of the lock bands and the brackets, and the number of components and man-hours increase.
The present invention has been made in view of the above circumstances, and provides a compound antenna apparatus enabling improvement of the tensile strength, reduction in the number of the components and the man-hours and space saving.